Electron tube



April 23, 1946. H. CONE AL 2,398,772

ELECTRON TUBE Filed Oct. 10, 1940 FlG. 1 FIG. 2

James H. Cone and Robert E. Mumma Inventors By awe/M Their AttorneyPatented Apr. 23, 1946 ELECTRON TUBE James H. Gone and Robert E. Momma,Dayton. Ohio, asslgnors to The National Cash Register Company, Dayton,Ohio, a corporation of Maryland Application October 10, 1940, Serial No.860,584 z'claims. (Clfill-27.5)

This invention relates to an electron gas discharge device and morespecificall pertains to one in which a current tapping member isprovided for collecting and utilizing the positive charges existing inthe conducting gaseous medium.

In introducing a current tapping member into an electron gas dischargetube for the collection of positive charges, it is desirable to give ita negative potential, that it may attract a greater number of positivecharges. It is also desirable to keep the negative charge on the currenttapping member from preventing a discharge in the tube. When anegatively biased grid is used to control the discharge in such a tube,it is desirable that the critical potential of the control grid be inthe negative region and yet that the negatively charged current tappingmember be positioned in the region of greatest conductivity.

Therefore, it is the principal object of this invention to provide agrid-controlled gas discharge electron tube having a current tappingmember for collecting positive charges from the conducting gas.

Another object of the invention is to provide such a tube wherein thecurrent tapping member is given a normal negative potential which is tobe reduced by the collection of positive charges when the tube isconducting.

Another object of the invention is to provide such an electron tubewherein a negatively biased control grid has a negative critical point.

Another object of the invention is to provide such an electron tubewherein the negatively charged current tapping member is in the regionof greatest conductivity but does not assume complete control of thedischarge.

With these and incidental objects in view, the invention includescertain novel features of construction and combinations of parts, theessential elements of which are set forth in appended claims and apreferred form or embodiment of which is hereinafter described withreference to the drawing which accompanies and forms a part of thisspecification.

of said drawing.

Fig. 1 is a perspective view of the tube with the envelope and otherparts broken away.

Fig. 2 is a section through the tube on the line 22 of Fig. 1.

Fig. 3 is a circuit utilizing the novel tube.

The tube comprises a gas-tight envelope l (Figs. 1 and 2)for instance,glasscontaining a press II, a seal it, and a gaseou medium 83- forinstance, one of the rare inert gases exemplined by neon and argon. ormercury vapor.

A cylindrical anode ll, having longitudinal has I! and It. is supportedin the envelope between two mica insulating discs 18 and ID, to whichthe anode is fastened by clips, the top disc 18 being clipped to fln Itby clip 20 and the bottom disc l9 being clipped to fin II by clip 2|.The mica discs themselves are supported and alined by the conductorwires 23 and 28 entering the tube through the press H. A conductor wireI! leads from the anode to the outside 0! the envelope through the sealii.

A cylindrical screen 22 is arranged within and coaxial with the anode llclose to the anode walls, being of equal length to the anode andsupported by the conductor wire 23, before described, entering theenvelope through the press II and piercing the mica discs :9 and III. Alongitudinal window 2| is cut in the current tapping screen member 22for its full length, except for support bands 25 and 26, to which areattached pins 30 and ll, which pierce the mica discs II and I9,respectively, to support and aline the screen with relation to the anodell.

A trough-shaped control grid 32 is disposed within the screen 22, itslong axis parallel to and substantially coaxial with the axis of theanode and the screen. its ends being bounded by the mica discs II andIt. The long opening or the trough faces the window i l of the screen22, the edges of said opening being approximately positioned in the sameradial lines from the coaxis as are the sides of window 24. The controlgrid is supported by the conductor wire 29, before mentioned, and by pin38 secured thereto, the ends or which pierce the mica discs.

A filament cathode 84, supported by hook 35, which is in turn fastenedto support 38 held in the press II. is disposed along and close to thecommon axis of the electrodes. The ends of the filament are connected toheater current conductors 38 and 39 entering through press II. A shieldcap 48 is supported by a band ll fastened to support 88. There is anelectrical connection between the cap I and the cathode filament llthrough hook it. A getter I0 is provided.

Electrons issuing from the filament cathode 8| through the troughopening of the grid 32 freely travel directly to the anode. However, theedges of the window 14 of the surrounding current tapping screen 22 arepositioned within the boundaries or the densest region 0! the positivecharges in the ionized gas. Thus, although the collector screen member"is negatively charged,

it has no absolute controlling influence on the trigger action of thetube, it being possible to cause the grid to lose control while it isstill nega... tively charged.

While the particular structure of the tube, as shown in the drawing, isthe most desirable embodiment of the invention, other arrangements ofthe elements relative to one another, as regards spacing andconfiguration, which perform the functions explained, are within thescope of the invention.

The utility of such a tube is shown in the circuit of Fig. 3, whichrepresents a typical portion of a system of electron tubes arranged tobe fired sequentially by positive electrical impulses impressed on allthe tubes simultaneously by a common conductor 65.

The tubes in such a system are interconnected in series by the same typeof circuits, and each tube is supplied with the same operating and cotrol potentials. An explanation or the network and circuit connectingthe two tubes shown will serve to disclose how any number of tubes maybe interconnected either in a straight series or in a non-ending ringseries.

The elements of the tubes in Fig. 3 bear the same reference numbers asthose of Figs. 1 and 2. The anodes ll are connected to a commonconductor 5|, each through a resistor 01 5,000 ohms like resistors 50.Conductor 5! is given a positive potential or 70 volts with respect toground and has in series with it and the source 01' potential a 100-ohmresistor 52. Conductor 5| is also grounded through a capacitor 53 of 1microiarad. The cathodes 34 are grounded. The current tapping screenmember 22 of one tube and the control grid 32 of the next tube in theseries have a common source of negative potential of 75 volts likesources 5i. Each current tapping screen member 22 has in series with itand its source of potential 54 a resistor, like resistors 58, of 500,000ohms. The control grid of the following tube oi the sequence has inseries with it and its source of potential 51 the same resistor 56 of500,000 ohms, as described, a resistor like resistors 50 of 100,000ohms, and a resistor like resistors SI of 50,000 ohms, Thus, each screen22 is connected to the control grid of the following tube throughresistors like resistors 58 and I I.

The characteristics of the gas discharge electron tube taken as anexample, as determined by the selection and spacing of the elements inthe tube, are such that with a positive anode potential or '70 volts andwith the collecting screen at 75 volts negative, the critical potential01' the control grid is 5 volts negative.

If tube I is "fired" and rendered conductive in any manner, as byrendering its control grid and current tapping screen member positivebeyond the critical points. the anode II will immediately drop inpotential to about volts positive. due to resistors 50 and 52. Currenttappin screen 22 is positioned by the disclosed method so as to collectenough positive charges to have its normal potential or '75 voltsnegative reduced to about 25 volts negative, which potential change istherefore impressed on control grid 32 of tube 11. Now, it a positive50-volt potential impulse is impressed on conductor 55, through eachcapacitor 08 and points 84, the control grid 32 of tube II will be givena positive pulse that takes it past the critical 5-volt negative point,and the tube II fires.

As tube 11 fires, its anode potential is reduced to approximately 15volts positive, due to resistors 50 and 52 in the anode supply. Thisdrop in poassay-rs tential causes a negative impulse of about 55 voltsto be impressed on conductor Ill through capacitor 03, which pulse is inturn impressed on the anode of every other tube in the connected seriesthrough their respective capacitors 81. As tube I is discharging, itsanode is at a potential of 15 volts positive, and the negative impulseof 55 volts will carry it more negative than the grounded cathode,extinguishing the discharge and allowing the control grid to resumecontrol. Thus, as tube II is fired after tube I by a 50-volt positivepotential impulse impressed on conductor 85, and tube I is extinguishedby a. 55-volt negative potential impulse impressed on conductor III bythe firing of tube H, so may any number of tubes so interconnected berendered conductive in sequence each by a single positive potentialimpulse.

This explanation is given to show how the negatively biased collectorscreen 22 is used to create a positive change in potential and how sucha positive change in potential may be utilized.

While the device herein shown and described is admirably adapted tofulfill the objects pri marily stated, it is to be understood that it isnot intended to confine the invention to the one form or embodimentherein disclosed, for it is susceptible oi embodiment in various formsall coming within the scope oi the claims which follow.

What is claimed is:

1. An electron tube, comprising a cathode; a control electrodesurrounding the cathode except for an aperture, whereby a suflicientnegative charge on the control electrode will prevent a discharge ofelectrons from the cathode and an insuilicient negative charge thereonwill allow electrons to be discharged through the aperture; a currenttapping electrode surrounding the control electrode except for anaperture for allowing a discharge of the electrons through the apertureof the control electrode to be unhindered, said current tappingelectrode being out of the zone of electron flow so as to have no totalcontrol over the discharge of electrons from the cathode; an anodesurrounding the cathode, the control electrode, and the current tappingelectrode; and an ionizable medium contained in an envelope surroundingthe anode, the cathode, the control electrode, and the current tap lngelectrode. whereby upon a discharge of electrons occurring from thecathode, the current tapping electrode will collect charges from theionizable medium.

2. An electron discharge device comprising an enclosing gas-filledenvelope containing a press; a cylindrical electron-receiving electrodehaving an electrical conductor connected thereto which pierces theenvelope through a seal, and having an insulating disc fastened to eachend; a cylindrical screen electrode disposed within theelectron-receiving electrode between the insulating discs and having acommon axis with the electron-receiving electrode, said screen electrodecontaining a longitudinal window; means secur- 1 18 the screen electrodeto the insulating discs and the press for support 01' theelectron-receiving electrode and the screen electrode, said securingmeans also issuing from the press as an electrical conductor to thescreen; a trough-shaped control electrode located centrally within thescreen electrode, its long axis being parallel with said common axis,and its longitudinal opening facing the window in the screen, thelongitudinal edges of the window and the edges or the opening beingsubstantially on the same radii from the common axis; means supportingthe control electhrough the press: and e shield cap positioned over oneend 01 the electron-receiving electrode and electrically connected tothe electron-emitting electrode.

JAMES H. CONE. ROBERT E. MUMIIA.

Certificate of Correction Patent No. 2,398,772.

April 23, 1946.

JAMES H. CONE ET AL.

It is hereby certified that errors appear in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second column, lines 51 and 52, strike out the words current tapping;line 55, or collector read current tapping; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the case in the Patent Oflice.

Signed and sealed this 2d day of July, A. D. 1946.

LESLIE FRAZER,

First Ass'olsicni Commissioner of Patents.

through the press: and e shield cap positioned over one end 01 theelectron-receiving electrode and electrically connected to theelectron-emitting electrode.

JAMES H. CONE. ROBERT E. MUMIIA.

Certificate of Correction Patent No. 2,398,772.

April 23, 1946.

JAMES H. CONE ET AL.

It is hereby certified that errors appear in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second column, lines 51 and 52, strike out the words current tapping;line 55, or collector read current tapping; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the case in the Patent Oflice.

Signed and sealed this 2d day of July, A. D. 1946.

LESLIE FRAZER,

First Ass'olsicni Commissioner of Patents.

